One: Pretreat. You can’t stop crabgrass once it starts, so apply a pre-emergent about the same time shrubs and trees start budding in your area.
Two: Kill any new weeds quickly. Even after an effective pretreatment, some weeds may find their way to the surface. Knock them out before they have time to mature and spread.
Three: Maintain a healthy lawn. Weeds thrive in weaker grass, so be sure to address any thinning or bare spots in your lawn.